Keyboard freezes when open a notification from a messaging app (such as Hangouts)

Unfortunately there is no solution yet. I am still trying to find a solution for this.

However many people reported that some of those workarounds worked for them:

1. Enable Click to open option on Interaction settings. 
2. Wait few seconds (4-5) between receiving a notification and opening it.
3. Use a different lock screen replacement app.
4. Disable Unlock on open option on Interaction settings and manually unlock the device right after opening it.

I hope that one of those workarounds will work for you and I really want to solve this issue soon but it might take some time because I can't reproduce it on my device and need to buy a new device to be able to reproduce it.